Cubic boron nitride sintered body and coated cubic boron nitride sintered body

Abstract

A cubic boron nitride sintered body including cubic boron nitride and a binder phase, wherein: a content of the cubic boron nitride is 81 volume % or more and 95 volume % or less and a content of the binder phase is 5 volume % or more and 19 volume % or less based on the total amount of the sintered body; and a content of Al in the binder phase is 0.5 mass % or more and 5 mass % or less, a content of W in the binder phase is 2 mass % or more and 10 mass % or less, a content of V in the binder phase is 2 mass % or more and 8 mass % or less, and a content of Cr in the binder phase is 0 mass % or more and 5 mass % or less, based on 100 mass % in total of all elements contained in the sintered body.

What is claimed is: 
     
         1 . A cubic boron nitride sintered body comprising cubic boron nitride and a binder phase, wherein
 a content of the cubic boron nitride is 81 volume % or more and 95 volume % or less based on a total amount of the sintered body,   a content of the binder phase is 5 volume % or more and 19 volume % or less based on the total amount of the sintered body,   a content of Al in the binder phase is 0.5 mass % or more and 5 mass % or less based on 100 mass % in total of all elements contained in the sintered body,   a content of W in the binder phase is 2 mass % or more and 10 mass % or less based on 100 mass % in total of all the elements contained in the sintered body,   a content of V in the binder phase is 2 mass % or more and 8 mass % or less based on 100 mass % in total of all the elements contained in the sintered body, and   a content of Cr in the binder phase is 0 mass % or more and 5 mass % or less based on 100 mass % in total of all the elements contained in the sintered body.   
     
     
         2 . The cubic boron nitride sintered body according to  claim 1 , wherein, in the binder phase, a ratio of a content (volume %) of a first material S1 composed of a compound containing W to a total content (volume %) of the first material S1 and a second material S2 composed of a compound being free of W and containing V, (S1/(S1+S2)), is 0.35 or more and 1 or less. 
     
     
         3 . The cubic boron nitride sintered body according to  claim 2 , wherein the total content (volume %) of the first material S1 and the second material S2 is 35 volume % or more and 97 volume % or less based on a total amount of the binder phase. 
     
     
         4 . The cubic boron nitride sintered body according to  claim 1 , wherein an average particle size of the cubic boron nitride is 0.5 μm or more and 3.0 μm or less. 
     
     
         5 . A coated cubic boron nitride sintered body comprising the cubic boron nitride sintered body according to  claim 1  and a coating layer formed on a surface of the cubic boron nitride sintered body,
 wherein an average thickness of the coating layer is 0.5 μm or more and 5.0 μm or less. 
 
     
     
         6 . The cubic boron nitride sintered body according to  claim 2 , wherein an average particle size of the cubic boron nitride is 0.5 μm or more and 3.0 μm or less. 
     
     
         7 . The cubic boron nitride sintered body according to  claim 3 , wherein an average particle size of the cubic boron nitride is 0.5 μm or more and 3.0 μm or less. 
     
     
         8 . A coated cubic boron nitride sintered body comprising the cubic boron nitride sintered body according to  claim 2  and a coating layer formed on a surface of the cubic boron nitride sintered body,
 wherein an average thickness of the coating layer is 0.5 μm or more and 5.0 μm or less. 
 
     
     
         9 . A coated cubic boron nitride sintered body comprising the cubic boron nitride sintered body according to  claim 3  and a coating layer formed on a surface of the cubic boron nitride sintered body,
 wherein an average thickness of the coating layer is 0.5 μm or more and 5.0 μm or less. 
 
     
     
         10 . A coated cubic boron nitride sintered body comprising the cubic boron nitride sintered body according to  claim 4  and a coating layer formed on a surface of the cubic boron nitride sintered body,
 wherein an average thickness of the coating layer is 0.5 μm or more and 5.0 μm or less. 
 
     
     
         11 . A coated cubic boron nitride sintered body comprising the cubic boron nitride sintered body according to  claim 6  and a coating layer formed on a surface of the cubic boron nitride sintered body,
 wherein an average thickness of the coating layer is 0.5 μm or more and 5.0 μm or less. 
 
     
     
         12 . A coated cubic boron nitride sintered body comprising the cubic boron nitride sintered body according to  claim 7  and a coating layer formed on a surface of the cubic boron nitride sintered body,
 wherein an average thickness of the coating layer is 0.5 μm or more and 5.0 μm or less.